Navigation device for dead reckoning

ABSTRACT

A navigation device is provided that includes a processor configured to track a path of the navigation device based on a first signal received by the navigation device, and calculate a calculated position of the navigation device based on a second signal different from the first signal. The navigation device may further include a graphical user interface configured to display a calculated position graphical element representing the calculated position determined based on the second signal and display a tracked position graphical element representing the path of the navigation device determined based on the first signal, the tracked position graphical element and the calculated position graphical element being distinguishable in appearance.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/046,426, filed Mar. 11, 2008 and entitled ON-BOARD DIAGNOSTICS BASEDNAVIGATION DEVICE FOR DEAD RECKONING, the entirety of which is herebyincorporated by reference for all purposes.

BACKGROUND

Portable electronic devices such as Personal Navigation Devices (PND)are increasingly utilized. A PND includes a Global Positioning System(GPS) receiver configured to receive signals from a group of artificialearth satellites called the Global Navigation Satellite System (GNSS).The GPS receiver uses the arrival time of signals from four or moresatellites to compute the distance to each satellite. From the relativedistances the GPS receiver is able to determine its position, andtherefore a user's position, using geometry and trigonometry.

In some cases a vehicle may be equipped with a navigation deviceintegrated with the vehicle's dashboard, and with the vehicle'selectronics. In other cases a portable PND may be brought into thevehicle, and may or may not receive power from the vehicle's powersupply. The detected position of the GPS receiver may be depicted as agraphical element superimposed over a map on a display to help a usernavigate. The graphical element may remain more or less in the samelocation on the display while the regions displayed on the superimposedmap adjust as the vehicle moves, illustrating movement of the useracross the map.

A problem sometimes arises when one or more of the signals from the GNSSare dropped. This may happen, for example, if the vehicle goes into atunnel, or travels adjacent one or more tall buildings, thereby blockingthe signal(s) from reaching the receiver. As a result, erroneous displayof the position of the vehicle on the map may occur, causing the user tobecome lost, confused, or miss a turn.

Efforts have been made to provide dead reckoning with PNDs by providinga PND with a built-in accelerometer. This approach has severaldrawbacks. First, this approach typically only provides dead reckoningfor a few seconds at a time. In addition, this approach involves adouble integration of the sensed acceleration, which causes accumulatederrors in speed and distance calculations.

SUMMARY

A navigation device is provided that includes a processor configured totrack a path of the navigation device based on a first signal receivedby the navigation device, and calculate a calculated position of thenavigation device based on a second signal different from the firstsignal. The navigation device may further include a graphical userinterface configured to display a calculated position graphical elementrepresenting the calculated position determined based on the secondsignal and display a tracked position graphical element representing thepath of the computing navigation device determined based on the firstsignal, the tracked position graphical element and the calculatedposition graphical element being distinguishable in appearance.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of a navigation system fordead reckoning, which includes a computing navigation device for usewith a vehicle;

FIG. 2 illustrates a first screen of a graphical user interface that isdisplayed on a display of the computing navigation device illustrated inFIG. 1, showing a tracked position and a calculated position of thecomputer navigation device as solid and dashed lines on a map;

FIG. 3 illustrates a second screen of the graphical user interface ofFIG. 2, showing a textual graphical element indicating that a computedroute based on a calculated position of the computing navigation deviceis being displayed;

FIG. 4A illustrates a third screen of the graphical user interface ofFIG. 2, showing a tracked position indicated by a solid line and a mappresented in a first color scheme; and

FIG. 4B illustrates a fourth screen of the graphical user interface ofFIG. 2, showing a calculated position indicated by a dashed line and amap presented in a second color scheme; and

FIG. 5 is a flowchart illustrating one embodiment of a method for deadreckoning.

DETAILED DESCRIPTION

FIG. 1 illustrates a navigation system 10 including a computingnavigation device 12 for use with a vehicle 22. The computing navigationdevice 12 may include a processor 14 configured to control, for example,a communication module 16, which is configured to receive one or moresignals 20 from a global positioning satellite (GPS) system 18. In theembodiments illustrated, the global positioning satellite (GPS) systemis the Global Navigation Satellite System (GNSS), although othersatellite positioning systems may be utilized. The signal 20 maycorrespond to a vehicle position of the vehicle 22. The correspondencemay be calculated by the computing navigation device 12 using knownmethods such as triangulation, or the like.

The computing navigation device 12 may further include a navigationmodule 56, which in turn includes a kinematic module 34, a signalmonitoring module 48, and an OBD data retrieval module 54. The signalmonitoring module 48 may be configured to recognize a dropped signalcondition in which no operational signal 20 is detected from the GPSsystem 18. The dropped signal condition may be detected, for example,when no GPS signals are received by the computing navigation device 12,or when fewer than a threshold number of GPS signals used to compute theposition of the computing navigation device 12 are received. Thethreshold number may be four, or another suitable number, for example,three.

The navigation module 56 of the computing navigation device 12 may alsobe configured to identify a last position 24 of the vehicle 22corresponding to a time of the dropped signal condition. The OBD dataretrieval module 54 may be configured to retrieve on-board diagnosticsdata, hereinafter referred to as OBD data 26, from an on-boarddiagnostics system 30 of the vehicle 22, the retrieved OBD data 26corresponding with a movement of the vehicle 22. The kinematic module 34may be configured to calculate a calculated position 36 of the vehicle22 based on the last position 24, and the OBD data 26 of the vehicle 22.

The signal monitoring module 48 may be configured to monitor the GPSsignal 20 from the communication module 16 and detect an operationalsignal condition or a dropped signal condition. The operational signalcondition indicates that a sufficient number and/or strength of signalsare detected to determine a position of the navigation device 12. Thedropped signal condition, as discussed previously, indicates that nooperational signal 20 is detected from the GPS system 18. Although thesignal module 48 is depicted as communicating through the communicationmodule 16 with the GPS receiver 21, it will be appreciated thatalternatively the signal monitoring module 48 may be configured tomonitor the signal directly from the GPS receiver 21.

As illustrated in FIG. 1 with decision box 50, if an operational signalcondition is detected, then the signal monitoring module 48 may pass thetracked position 46 to the graphical user interface 42 displayed ondisplay 40 via, for example, a graphical user interface 52. But, if nooperational signal is detected, which may occur if no signal at all isdetected, if the signal strength is below a predetermined threshold, orif signals are detected only from a number of satellites that is below apredetermined threshold and thus insufficient to determine a position ofthe navigation device 12, then the signal monitoring module 48 isconfigured to recognize this situation as a dropped signal condition. Inresponse to detecting the dropped signal condition, the signalmonitoring module 48 is configured to pass the last position 24 to thekinematic module 34, and communicate with the OBD data retrieval module54 to pass OBD data 26 to the kinematic module 34. Alternatively, thesignal monitoring module 48 is configured to communicate the droppedsignal condition directly to the kinematic module 34, which in responseis configured to receive OBD data 26 from the communications module 16.

The on-board diagnostics system 30 may be configured to generate OBDdata 26, and transmit the OBD data to the communication module 58 viaOBD port 59. The OBD port 59 may be a virtual or physical port, and mayeffect a coupling of the on-board diagnostics system 30 to the computingnavigation device 12. The computing navigation device 12 and on-boarddiagnostics system 30 may be coupled via a wired or wireless coupling,for example.

The OBD data 26 generated by the on-board diagnostics system 30 may beorganized to include a plurality of parameters, each of which mayinclude a parameter identifier, and an associate value. The parametersmay be used by vehicle technicians to diagnose a vehicle condition. Someparameters may be industry standard parameters 76 utilized by multiplevehicle manufacturers, while others may be model-specific parameters 78used by the manufacturer of a specific vehicle model.

Example standard parameters 76 that the on-board diagnostics system 30may be configured to provide include a speed 70 and a steering wheelposition 72 of the vehicle 22. Example model specific parameters 78include a cardinal direction 74 sensed by a compass outfitted on thevehicle 22. Thus, it will be appreciated that the kinematic module 34may be configured to calculate the calculated position 36 based on oneor more of the speed 70, the steering wheel angle 72, and the cardinaldirection 74, among other parameters. It should be understood theseparameters are merely exemplary, and various other parameters may beused to effect dead reckoning as well.

The kinematic module 34 may be further configured to calculate anupdated calculated position of the vehicle 22 based on the calculatedposition 36 and updated OBD data 26 from the on-board diagnostics system30. This may be done iteratively such that a substantially continuouslyupdated vehicle position may be displayed on the graphical userinterface 42 on display 40 from a substantially continuously updatedcalculated position 36. The updating of the calculated position 36 mayoccur until a signal of sufficient strength is detected by the signalmonitoring module 48, at which time the navigation module 56 maydetermine a new tracked position 46, which may be displayed on thegraphical user interface 42 on display 40.

The computing navigation device 12 may include a graphical userinterface module 52 that is configured to render a graphical userinterface 42 on display 40. The graphical user interface module 52 maybe configured to display a representation of the tracked position 46 ofthe vehicle 22 based on the GPS system signal 20, and the calculatedposition 36 based on the OBD data, on the graphical user interface 42 ondisplay 40.

In some embodiments, the graphical user interface 42 also may beconfigured to receive a user input to effect selected retrieval of theOBD data 26. For example, during a setup procedure the user may inputmodel information of the user's vehicle, so that model specificparameters 78 may be utilized. As another example, the user may inputuser preferences for the type of standard parameters 76 to be utilized.It will be appreciated that the computing navigation device may defaultto receiving the standard parameters indicating speed and steering wheelposition, and a user may choose additional parameter options. Throughsuch a set up procedure, the OBD data 26 for retrieval may be selectedby the user from one or more standard parameters 76, and/or one or moremodel specific parameters 78.

The communication module 16, the navigation module 56 and the interfacemodule 52 may all be stored in a memory 58 that is associated with theprocessor 14. The memory may include non-volatile memory and volatilememory, and the processor 14 may be configured to execute the modulesusing portions of each.

FIGS. 2, 3, 4A, and 4B illustrate various screens of graphical userinterface 42. The graphical user interface 42 may be configured todisplay the tracked position 46 of the vehicle 22 via a tracked positiongraphical element 60 during a signal receiving condition which includesan operational signal being received from the GPS system 18 that enablesthe tracking of the position of the computing navigation device. Thegraphical user interface 42 may be further configured to display thecalculated position 36 of the vehicle 22 via a calculated positiongraphical element 62 during the dropped signal condition. As describedbelow in further detail, the tracked position graphical element 60 andthe calculated position graphical element 62 are distinguishable inappearance.

For example, as illustrated in FIG. 2, the tracked position graphicalelement 60 may be a line of a first pattern, color and/or thickness,such as a solid line 61, depicting the movement of the vehicle 22 alonga map 64 while the navigation module 56 receives a signal 20 from theGPS system 18. The calculated position graphical element 62 may be aline of a second pattern, color and/or thickness, such as a dashed ordotted line 63, depicting the movement of the vehicle 22 along the map64. Other combinations of distinguishable lines may alternatively beused, such as two different dashed lines, two different colored lines,or lines of two different thicknesses, etc. Some embodiments may includea dropped signal graphical element 65 and/or a signal restored element67. These elements may also aid the user's awareness of the signalcondition.

As shown in FIG. 3, the tracked position graphical element 60 may be aline superimposed on a depiction of the map 64, and the calculatedposition graphical element 62 may be a floating graphical element on thedisplay during the dropped signal condition such as a text item 71indicting to the user that the GPS signal has been dropped, and theroute is being calculated rather than tracked. The text item 71 mayflash or change color to increase visibility. It will be appreciatedthat other types of floating graphical elements may also be used, suchas graphical icons, letters, numbers, etc.

Another example embodiment is illustrated in FIGS. 4A and 4B wherein thetracked position graphical element 60 may be a depiction of the map 64and/or the entire display displayed in a first color scheme, asschematically depicted with bold lines and hatching in FIG. 4A. Thecalculated position graphical element 62 may be a depiction of the map64 and/or the entire display being displayed in a second color scheme,as schematically depicted with relatively thinner lines in FIG. 4B. Inother embodiments in which the color scheme of the map or displaychanges to indicate that the position of the vehicle is beingcalculated, a graphical depiction of the traveled path may be omittedfrom the display, such that the current position of the vehicle is shownby a graphical element, but prior calculated positions are not shown.

Some embodiments may include a graphical element depicting the locationof the vehicle that may remain in substantially the same location on thedisplay while the regions displayed on the superimposed map adjust asthe vehicle moves, depicting movement of the vehicle across the map.Comparison of FIG. 2 to FIG. 3 illustrates such movement although otherfeatures of FIG. 2 have been included to illustrate other aspects ofvarious embodiments.

FIG. 5 is a flow chart illustrating an embodiment of a method for deadreckoning. The method may be implemented using the hardware and softwarecomponents of navigation system 10 described above, or using othersuitable hardware and software. The method 200 may include, at 202,receiving a GPS signal from a GPS system having a GPS receiver and beingcoupled with a moving vehicle. At 204, the method may includerecognizing a lack of operational signal from the GPS system as adropped signal condition. At 206, the method may include passing a lastposition of the vehicle to a kinematic module upon reaching the droppedsignal condition. The passing of the last position may be effected uponrecognizing a lack of signal from the GPS system by a signal monitoringmodule, and the method may further include communicating with an OBDdata retrieval module to pass the OBD data to the kinematic module uponrecognizing the lack of signal from the GPS system.

At 208, the method may include retrieving OBD data corresponding with acontinued movement of the vehicle from an on-board diagnostics system ofthe vehicle, and passing the OBD data to the kinematic module. Asdiscussed above, retrieving OBD data from the on-board diagnosticssystem may include retrieving one or more of the speed of the vehicle,the steering wheel angle, and the cardinal direction, among otherparameters. In some embodiments, the data is retrieved based on userinput instructions that are received from a graphical user interface toeffect changes in the display or calculation of the position of thevehicle. At 210, the method may include calculating a calculatedposition of the vehicle with the kinematic module based on the lastposition of the vehicle and the OBD data. As discussed above,calculating the calculated position may include performing a calculationbased on one or more of a speed of the vehicle, a steering wheel angle,and a cardinal direction, among other parameters. At 212, the method mayinclude displaying the calculated position of the vehicle on a graphicaluser interface.

Some embodiments may provide a method that may further includedisplaying a tracked position of the vehicle on the graphical userinterface based on the stream of signals from GPS system. Displaying thetracked position of the vehicle may include displaying the position ofthe vehicle via a tracked position graphical element during a signalreceiving condition indicating that an operational signal is beingreceived from the GPS system, and the displaying the calculated positionof the vehicle may include displaying the position of the vehicle via acalculated position graphical element during the dropped signalcondition. The tracked position graphical element and the calculatedposition graphical element may be distinguishable in appearance in thevarious manners described above.

The systems and methods described above may enable efficient calculationof a position of a vehicle upon loss of the ability to sufficientlytrack the position of the vehicle using global positioning satellites,reducing potential confusion to vehicle operators.

It will be appreciated that the computing navigation device describedherein may be any suitable computing device configured to execute theprograms described herein. For example, the computing navigation devicemay be a personal computer, laptop computer, portable data assistant(PDA), computer-enabled wireless telephone, networked computing device,or other suitable computing device, and may be connected to a computernetwork, such as the Internet. The computing device typically includes aprocessor and associated volatile and non-volatile memory, and isconfigured to execute programs stored in non-volatile memory usingportions of volatile memory and the processor. As used herein, the terms“program” and “module” refers to software or firmware components thatmay be executed by, or utilized by, one or more computing devicesdescribed herein, and is meant to encompass individual or groups ofexecutable files, data files, libraries, drivers, scripts, databaserecords, etc. It will be appreciated that computer-readable media may beprovided having program instructions stored thereon, which uponexecution by a computing device, cause the computing device to executethe methods described above and cause operation of the systems describedabove.

It should be understood that the embodiments herein are illustrative andnot restrictive, since the scope of the invention is defined by theappended claims rather than by the description preceding them, and allchanges that fall within metes and bounds of the claims, or equivalenceof such metes and bounds thereof are therefore intended to be embracedby the claims.

1. A navigation device, comprising: a processor configured to: track apath of the navigation device based on a first signal received by thenavigation device; and calculate a calculated position of the navigationdevice based on a second signal different from the first signal; and agraphical user interface configured to display a calculated positiongraphical element representing the calculated position determined basedon the second signal and display a tracked position graphical elementrepresenting the path of the navigation device determined based on thefirst signal, the tracked position graphical element and the calculatedposition graphical element being distinguishable in appearance.
 2. Thenavigation device of claim 1, wherein the processor is furtherconfigured to: receive as the first signal a global positioningsatellite (GPS) system signal; and display the tracked positiongraphical element based on the first signal during a signal receivingcondition indicating that the first signal is being received.
 3. Thenavigation device of claim 2, wherein the processor is furtherconfigured to: recognize a dropped signal condition in which anoperational first signal is not received and a position of thenavigation device cannot be tracked; identify a last tracked position ofthe navigation device corresponding to a time of the dropped signalcondition; calculate the calculated position of the navigation devicefrom the last tracked position based on the second signal during thedropped signal condition; and display the calculated position graphicalelement at least during the dropped signal condition.
 4. The navigationdevice of claim 1, wherein: the tracked position graphical element is aline of a first pattern depicting the movement of the navigation devicealong a map; and the calculated position graphical element is a line ofa second pattern depicting the movement of the navigation device alongthe map.
 5. The navigation device of claim 1, wherein: the trackedposition graphical element is a line of a first color depicting themovement of the navigation device along a map; and the calculatedposition graphical element is a line of a second color depicting themovement of the navigation device along the map.
 6. The navigationdevice of claim 1, wherein: the tracked position graphical element is aline of a first thickness depicting the movement of the navigationdevice along a map; and the calculated position graphical element is aline of a second thickness depicting the movement of the navigationdevice along the map.
 7. The navigation device of claim 1, wherein thecalculated position graphical element is selected from the groupconsisting of a text item, graphical icon, letter, number, and colorscheme.
 8. The navigation device of claim 1, wherein the navigationdevice is on board a vehicle, and wherein the first signal includeson-board diagnostic (OBD) data retrieved from an on-board diagnosticsystem of the vehicle.
 9. The navigation device of claim 8, wherein theprocessor is further configured to: receive the first signal includingthe OBD data corresponding with a movement of the vehicle from theon-board diagnostics system; and calculate the calculated position froma last tracked position of the vehicle at the time the dropped signalcondition was recognized, based on the OBD data.
 10. The navigationdevice of claim 9, wherein the OBD data includes a speed, a steeringwheel angle, and a cardinal direction of the navigation device.
 11. Thenavigation device of claim 10, wherein the processor is configured toexecute a kinematic module to calculate the calculated position of thenavigation device, and wherein the kinematic module is configured tocalculate the calculated position based on one or more of the speed ofthe navigation device, the steering wheel angle, and the cardinaldirection in the OBD data.
 12. A method for dead reckoning, comprising:tracking a path of a navigation device based on a first signal receivedby the navigation device; and calculating a calculated position of thenavigation device based on a second signal different from the firstsignal; and displaying a graphical user interface including a calculatedposition graphical element representing the calculated positiondetermined based on the second signal and displaying a tracked positiongraphical element representing the path of the navigation devicedetermined based on the first signal, the tracked position graphicalelement and the calculated position graphical element beingdistinguishable in appearance.
 13. The method of claim 12, furthercomprising: receiving as the first signal a global positioning satellite(GPS) system signal; and displaying the tracked position graphicalelement based on the first signal during a signal receiving conditionindicating that the first signal is being received.
 14. The method ofclaim 13, further comprising: recognizing a dropped signal condition inwhich an operational first signal is not received and a position of thenavigation device cannot be tracked; identifying a last tracked positionof the navigation device corresponding to a time of the dropped signalcondition; calculating the calculated position of the navigation devicefrom the last tracked position based on the second signal during thedropped signal condition; and displaying the calculated positiongraphical element at least during the dropped signal condition.
 15. Themethod of claim 12, wherein: the tracked position graphical element is aline of a first pattern, color and/or thickness, depicting the movementof the navigation device along a map; and the calculated positiongraphical element is a line of a second pattern, color and/or thickness,depicting the movement of the navigation device along the map.
 16. Themethod of claim 12, wherein the navigation device is on board a vehicle,and wherein the first signal includes on-board diagnostic (OBD) dataretrieved from an on-board diagnostic system of the vehicle.
 17. Themethod of claim 16, further comprising: receiving the first signalincluding the OBD data corresponding with a movement of the vehicle fromthe on-board diagnostics system; and calculating the calculated positionfrom a last tracked position of the vehicle at the time the droppedsignal condition was recognized, based on the OBD data.
 18. The methodof claim 16, wherein receiving the first signal including the OBD datafrom the on-board diagnostics system includes receiving one or more of aspeed, a steering wheel angle, and a cardinal direction of the vehicle.19. The method of claim 16, wherein calculating the calculated positionfrom the last tracked position of the vehicle includes performing acalculation based on one or more of a speed, a steering wheel angle, anda cardinal direction of the vehicle.
 20. A computer readable storagemedium comprising stored instructions that when executed by a processorof a navigation device cause the navigation device to: track a path ofthe navigation device based on a first signal received by the navigationdevice; and calculate a calculated position of the navigation devicebased on a second signal different from the first signal; and display ona graphical user interface a calculated position graphical elementrepresenting the calculated position determined based on the secondsignal and display a tracked position graphical element representing thepath of the navigation device determined based on the first signal, thetracked position graphical element and the calculated position graphicalelement being distinguishable in appearance.
 21. The computer readablestorage medium of claim 20, further comprising stored instructions thatwhen executed by the processor of the navigation device cause thenavigation device to: receive as the first signal a global positioningsatellite (GPS) system signal; and display the tracked positiongraphical element based on the first signal during a signal receivingcondition indicating that the first signal is being received.
 22. Thecomputer readable storage medium of claim 21, further comprising storedinstructions that when executed by the processor of the navigationdevice cause the navigation device to: recognize a dropped signalcondition in which an operational first signal is not received and aposition of the navigation device cannot be tracked; identify a lasttracked position of the navigation device corresponding to a time of thedropped signal condition; calculate the calculated position of thenavigation device from the last tracked position based on the secondsignal during the dropped signal condition; and display the calculatedposition graphical element at least during the dropped signal condition.23. The computer readable storage medium of claim 20, further comprisingstored instructions that when executed by the processor of thenavigation device cause the navigation device to: display the trackedposition graphical element as a line of a first pattern, color and/orthickness, depicting the movement of the navigation device along a map;and display the calculated position graphical element as a line of asecond pattern, color and/or thickness, depicting the movement of thenavigation device along the map.
 24. The computer readable storagemedium of claim 20, wherein the navigation device is on board a vehicle,and wherein the first signal includes on-board diagnostic (OBD) dataretrieved from an on-board diagnostic system of the vehicle.